On Wed, Mar 12, 2014 at 09:04:01AM -0700, Darwin Rambo wrote:
The reason for this change is to be able to use the ARM Trusted Firmware (ATF) to load the various ATF images, plus u-boot, which can then load the kernel/ramdisk/dtb with calls to an external host from a standard fastmodel armv8 board file using semihosting, and then launch the kernel without a bootwrapper. This gives us a more realistic boot sequence.
Rather than create a new armv8 board similar to armltd/vexpress64, add semihosting calls to the existing one, enabled with CONFIG_SEMIHOSTING. Also add a new board config file vexpress_aemv8a_semi.h. This change is tested and works on the ARM foundation model.
Support for armv7 in fastmodel is less useful due to the wide range of available silicon but this change contains an untested armv7 placeholder if desired.
The level of semihosting support is minimal, restricted to just what it takes to load images to memory. If more semihosting functionality is required, such as file seek, outputting strings, reading characters, etc, then it can be easily added later.
Signed-off-by: Darwin Rambo drambo@broadcom.com
At the high-level, I'm fine with this. But as an implementation detail we need to either leverage vexpress_common.h or create a vexpress_arm64_common.h or something. There's a lot in common between these two configs, and some further clean-up we need to do to the first one anyhow.
Next:
+#ifdef CONFIG_BOARD_LATE_INIT +int board_late_init(void) +{ +#ifdef CONFIG_SEMIHOSTING
- /*
* We require that the board include file defines these env variables:* - kernel_addr* - initrd_addr* - fdt_addr** For the "fdt chosen" startup macro, this code will then define:* - initrd_end (based on initrd_base plus actual initrd_size)** We will then load the kernel, initrd, and fdt into the specified* locations in memory in a similar way that the ATF fastmodel code* uses semihosting calls to load other boot stages and u-boot itself.*/- /* Env variable strings */
- char *kernel_addr_str = getenv("kernel_addr");
- char *initrd_addr_str = getenv("initrd_addr");
- char *fdt_addr_str = getenv("fdt_addr");
- char initrd_end_str[64];
First, we need to document this stuff in a README file as well. Second, I'd like to see kernel_addr_r / ramdisk_addr_r / fdt_addr_r used to match-up with what Dennis Gilmore has been working on to get a common env working.
[snip]
- /* Assumes kernel is lower in memory than fdt */
- smh_load(CONFIG_KNLNAME, kernel_addr, fdt_addr - kernel_addr, 1);
- /* Load fdt to memory */
- smh_load(CONFIG_FDTNAME, fdt_addr, 0x20000, 1);
- /* Load initrd to memory */
- smh_load(CONFIG_RDNAME, initrd_addr, initrd_size, 1);
Is there a reason we can't also get these from the environment? Or a limitation of (how we support) the simulator that we don't have persistent r/w environment right now?
Thanks!